1. Field of the Invention
This invention is directed to an isolated intelligent and interrelated control system to satisfy the demand of a boiler and in which a boiler demand signal is applied to control the rate of grinding of the fuel material and in which each isolated unit has manual substitute control which can be used in the event of a control unit failure to automatically or manually supply the boiler with ground fuel which has a desired temperature and particle size adequate to maintain desired boiler operation.
2. Description of the Prior Art
It is known that coal grinding apparatus for direct coal fired burners is regulated by a boiler computer which regulates the speed controlled roller grinding mills operated in cooperation with a speed controlled spinner separator which determines the particle size and coal feeder to match the burner requirements. Fuel feeders of the above type employ controls measuring fluid bed differential pressure across the roller mill resulting in an expression of the quantity of fuel in the grinding mill so the mill grinding rolls can perform efficiently in producing a satisfactory output.
The known examples of prior art are adapted to domestic installations while malfunctioning apparatus can be corrected or worked upon by service personnel who understand the apparatus operation. However, when such apparatus is selected for installations in non-English countries where foreign language directions apply, there is great difficulty in securing proper service results in the event of malfunctioning of any component of the system. At the present time domestic apparatus used in a non-domestic environment is difficult to service in the event of a breakdown of a control unit. Language barriers prevent prompt attention to problems that interfere with apparatus repair.